The main factor that may weaken the stability of the roof structure is dampness. On its negative impact it is particularly exposed rafter framing, which deform under impact of water. Therefore is important roof protection against getting in  water into its internal structure.

Typically, investors during the construction of the roof attach great importance both for building materials, as well as careful execution. Unfortunately, later very often they forget about the survey, and any minor defects  commission outsource cheaper and often non-professional roofing companies. This is a big mistake,

CHAPTERROOFCEILING CONSTRUCTION international residential code 2006, new jersey editionroofceiling construction table r802.41—continued ceiling joist spans for common lumber species Replacement Windows in Michigan and Ohio. Siding, Roofing. Replacement Windows in Michigan and Ohio; Hansons vinyl replacement windows set the standard efficiency and window value. Vinyl

A very important element that must be considered when the roof is projected, is ventilation, allowing drainage of excess dampness from under the roofing.